The Bureau of Meteorology (BoM) has warned of severe weather throughout significant areas of eastern Australia as two weather systems brought rain and thunderstorms across a large area.

While the location and timing of falls are uncertain, falls of between 80-100 millimetres could eventuate in parts of NSW and totals of 20-50mm common for Victoria.

Tropical Cyclone Owen was currently moving slowly westward in the Gulf of Carpentaria as a category one system, and the current forecast indicates an intensifying trend to category two late on Wednesday, and category three by Thursday morning.

BoM extreme weather desk manager James Taylor said Owen was then expected to move toward the east on Friday and into the weekend, bringing large rainfall totals and strong winds to northern Queensland.

"Heavy rainfall potential exists for much of coastal Queensland during the weekend, with Tropical Cyclone Owen forecast to move southward," Mr Taylor said.

"Meanwhile a low pressure system is forecast to develop over Victoria during Thursday.

“The low looks likely to gradually move to south-western NSW on Friday then southwards during the weekend to be south of Tasmania by Sunday night.

"This system has the potential to draw moisture southward from Tropical Cyclone Owen, creating a large cloudband with associated severe thunderstorms along much of the east of the continent.

"Heavy rainfall associated with the cloudband looks likely to affect Victoria on Thursday then contract southwards during Friday.

He said south-eastern South Australia and northern and eastern Tasmania may also be affected by heavy rainfall over the next few days.

Severe thunderstorms within the cloud band are predicted for eastern NSW, however associated heavy rainfall is likely to be sporadic in nature.

On Wednesday, the BoM was forecasting falls of 25-50mm in the four-day period across almost all of Victoria.

Parts of South Gippsland were expecting 50-100mm.

For the same forecast period, rainfall totals for the NSW Central West, Tablelands and north, as well as much of western and central Queensland, were expected to range between 25-50mm.

The north of NSW could receive more than 50mm.

While rain will be detrimental to the harvest, southern Victoria would benefit from a boost in moisture levels for pasture production and regrowth after silage and hay making operations.

Livestock agents also report that the forecast falls north of the border could be a boom for coming sales.

Some earlier rains have seen small, but important, loads of cattle head north and more rain could see a jump in buyer inquiry.

BoM acting senior forecaster Alain Baillie said the forecast was for a cut off low to develop late Wednesday into Thursday.

The nature of a cut off low meant that a pool of cool air and cold front from the southern ocean became “cut off” from the westerly stream causing the system to lose that stream and stall for an extended period.

Areas of Victoria also received falls of between 12-25mm across the northern country, North-East and north central forecast areas over last Sunday.

These falls were due to fast moving thunderstorms, with Mount Wombat measuring 36mm and Bendigo 27mm.

Other totals were Maryborough 17mm, Redesdale and Euroa 13mm, and Shepparton and Echuca 12mm.

Areas such as Ballarat received just 4mm and Donald measured 3mm.

Wunghnu farmer Stuart Hipwell said the area missed most of the weekend’s storms.

He measured just 7mm which was “no value”.

“We have had only 196mm for the year so far. It’s surprising though how well the paddocks that had been irrigated reacted to rain we had in October,” he said.

He said the forecast heavy falls for later in the week were too late for most but may add some sub soil moisture for croppers.

“It only brings up summer weeds, but it may boost dam levels,” he said.